New Views on Advanced Visualization

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 - CT of AAA repair
CT of AAA repair highlighting the transplanted celiac trunk (blue), SMA (green), renal arteries (orange/ purple), and thrombosed AAA in yellow.
Source: Clinical data courtesy of Duke University. Images courtesy of Ziosoft
Advanced visualization has become routine visualization, an essential part of the radiologist’s toolkit. The challenges and potential of advanced visualization technology represent a microcosm of radiology. These technologies need to demonstrate increased efficiency and value as radiologists wrestle with declining reimbursement and increasing demands. The answers parallel those that will deliver benefits across radiology—beefier integration, minimal hardware and an enterprise mindset.

“Advanced visualization is no longer just a curiosity. Many surgeons have become highly dependent on our 3D renderings, and use them to decide whether to take a patient to the operating room,” says Myron A. Pozniak, MD, professor of abdominal imaging at the University of Wisconsin School of Medicine and Public Health in Madison.

Indeed, the utility of 3D is expansive. “We look at almost every CT with some type of advanced visualization software. There are so many slices of sub-millimeter thickness. To look at every slice is tedious and increases the chance that the radiologist will miss an abnormality,” says Henry J. Krebs, MD, medical director of interventional radiology at St. Joseph’s Hospital of Atlanta.  

The enthusiasm for advanced visualization transcends the reading room. Without 3D reconstruction, vascular access can be a tortuous endeavor for surgeons; 3D renderings illustrate impediments and provide a roadmap not possible with simple axial slices. “It saves the surgeon time and ultimately improves patient safety,” notes Krebs.

Indeed, CT angiography (CTA) and MR angiography (MRA) have banished diagnostic carotid angiography to yesteryear, notes Charles L. Truwit, MD, a neuroradiologist at University of Minnesota Medical Center in Minneapolis. A patient only undergoes an invasive diagnostic angiogram when the clinician knows the patient requires treatment.

“When vascular stenting is being considered for a patient, careful analysis of a CTA or MRA dataset allows interventionalists or surgeons to precisely determine the kind and size of device before the procedure. They are more confident that the stent can be deployed appropriately and with a tight seal,” explains Pozniak. This decreases failure rates and the need for revascularization.

Despite the clinical utility of 3D reconstructions, the technology is not without challenges. “Bundled codes have really complicated the picture dramatically for evaluation of stroke, subarachnoid hemorrhages and aneurysms,” says Truwit.

Meanwhile, the mantra in advanced visualization has been taking the technology to the next level. The implied assumption is that enterprise advanced visualization is the next level. “While we need to reach the enterprise level, the goal is to get advanced visualization on workstations or iPads to eliminate hardware costs. And we need to cut the time for an evaluation of the head or body to 90 seconds or less,” says Truwit. Doing so could meet radiologists’ efficiency, financial and clinical needs.

The 3D lab conundrum

Truwit has honed efficiency to a science, completing a rendering of the Circle of Willis in 90 seconds. Although he eschews the 3D lab model, he believes advanced visualization developers need to automate the generation of the images. At high-volume sites that handle three studies an hour, this could eliminate the need for a full-time radiologist, representing a minimum savings of at least $300,000.

At St. Joseph’s, radiologists also complete most reconstructions. “The problem then becomes how long it takes for radiologists to complete processing,” admits Krebs.

In contrast, the University of Wisconsin department of radiology utilizes a 3D lab model, employing specialized technologists to create basic 3D renderings. Why? A simple extremity runoff may be completed in 10 to 15 minutes, but more complex studies such as hepatic renderings can stretch to an hour or longer.

With the 3D lab approach, the supertech completes initial renderings. The radiologist reviews and tweaks them and identifies projections for the archive.

While cost effective, this model may not be the optimal clinical solution, as 3D utility and radiology reimbursement hinge on detecting abnormalities that aren’t easily seen. “When someone performs 3D for you, you only see what they thought they saw. The only way to do conduct advanced visualization really well is for the radiologist to be hands-on,” states Elliot K. Fishman, MD, director of diagnostic imaging and body CT at Johns Hopkins University School of Medicine in Baltimore.
Plus, when the radiologist performs reconstructions, it solidifies 3D as the radiologist’s business, says Fishman.

The goal, continues Fishman, is real-time interactivity. Cloud computing and iPads support interactive 3D, he says, and make it easier for physicians to access studies, which boosts efficiency and clinical value. Truwit adds that cloud computing can cut back-end hardware costs.

Another challenge is the lack of PACS integration. Three-dimensional renderings typically require a manual push to the archive, an undertaking that can cut into radiologists’ efficiency. Krebs dubs his solution PACS 2.0, a multimedia system that would wed text and images in a content-specific manner and employ structured reporting to direct clinicians to the information they need in the report and images.

In the interim, many PACS vendors have integrated some advanced visualization tools. “Multiplanar viewing on PACS has become more robust,” offers Pozniak. “We can perform more multiplanar reformatting of the axial dataset and interact more with those datasets before jumping to the 3D workstation.”

However, true 3D tools such as CT colon-ography and lung CAD are likely to remain in the realm of the 3D vendor with the onus on PACS vendors to streamline integration of 3D packages.

“We can add words to images, but there is nothing better than a well-rendered 3D reconstruction. An image may be worth a thousand words but a good 3D rendering is worth a thousand images,” affirms Pozniak.

Although advanced visualization has become routine, the technology faces ongoing challenges ranging from reimbursement cuts to integration issues. However, facilities are honing their operations, communicating needs to vendors for next-generation incorporation and sharing capabilities with clinicians to enhance their programs.